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Main Authors: Reeves, Cian, Kurniawan, Michael, Zhu, Yuanran, Jampana, Nikil, Brown, Jacob, Yang, Chao, Ibrahim, Khaled, Vlcek, Vojtech
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.00667
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author Reeves, Cian
Kurniawan, Michael
Zhu, Yuanran
Jampana, Nikil
Brown, Jacob
Yang, Chao
Ibrahim, Khaled
Vlcek, Vojtech
author_facet Reeves, Cian
Kurniawan, Michael
Zhu, Yuanran
Jampana, Nikil
Brown, Jacob
Yang, Chao
Ibrahim, Khaled
Vlcek, Vojtech
contents Time-resolved spectroscopy is a powerful tool for probing electron dynamics in molecules and solids, revealing transient phenomena on sub-femtosecond timescales. The interpretation of experimental results is often enhanced by parallel numerical studies, which can provide insight and validation for experimental hypotheses. However, developing a theoretical framework for simulating time-resolved spectra remains a significant challenge. The most suitable approach involves the many-body non-equilibrium Green's function formalism, which accounts for crucial dynamical many-body correlations during time evolution. While these dynamical correlations are essential for observing emergent behavior in time-resolved spectra, they also render the formalism prohibitively expensive for large-scale simulations. Substantial effort has been devoted to reducing this computational cost -- through approximations and numerical techniques -- while preserving the key dynamical correlations. The ultimate goal is to enable first-principles simulations of time-dependent systems ranging from small molecules to large, periodic, multidimensional solids. In this perspective, we outline key challenges in developing practical simulations for time-resolved spectroscopy, with a particular focus on Green's function methodologies. We highlight a recent advancement toward a scalable framework: the real-time Dyson expansion (RT-DE). We introduce the theoretical foundation of RT-DE and discuss strategies for improving scalability, which have already enabled simulations of system sizes beyond the reach of previous fully dynamical approaches. We conclude with an outlook on future directions for extending RT-DE to first-principles studies of dynamically correlated, non-equilibrium systems.
format Preprint
id arxiv_https___arxiv_org_abs_2505_00667
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Practical Framework for Simulating Time-Resolved Spectroscopy Based on a Real-time Dyson Expansion
Reeves, Cian
Kurniawan, Michael
Zhu, Yuanran
Jampana, Nikil
Brown, Jacob
Yang, Chao
Ibrahim, Khaled
Vlcek, Vojtech
Computational Physics
Time-resolved spectroscopy is a powerful tool for probing electron dynamics in molecules and solids, revealing transient phenomena on sub-femtosecond timescales. The interpretation of experimental results is often enhanced by parallel numerical studies, which can provide insight and validation for experimental hypotheses. However, developing a theoretical framework for simulating time-resolved spectra remains a significant challenge. The most suitable approach involves the many-body non-equilibrium Green's function formalism, which accounts for crucial dynamical many-body correlations during time evolution. While these dynamical correlations are essential for observing emergent behavior in time-resolved spectra, they also render the formalism prohibitively expensive for large-scale simulations. Substantial effort has been devoted to reducing this computational cost -- through approximations and numerical techniques -- while preserving the key dynamical correlations. The ultimate goal is to enable first-principles simulations of time-dependent systems ranging from small molecules to large, periodic, multidimensional solids. In this perspective, we outline key challenges in developing practical simulations for time-resolved spectroscopy, with a particular focus on Green's function methodologies. We highlight a recent advancement toward a scalable framework: the real-time Dyson expansion (RT-DE). We introduce the theoretical foundation of RT-DE and discuss strategies for improving scalability, which have already enabled simulations of system sizes beyond the reach of previous fully dynamical approaches. We conclude with an outlook on future directions for extending RT-DE to first-principles studies of dynamically correlated, non-equilibrium systems.
title A Practical Framework for Simulating Time-Resolved Spectroscopy Based on a Real-time Dyson Expansion
topic Computational Physics
url https://arxiv.org/abs/2505.00667